Chemical formula: Al₂O₃

Chemical purity: 2N5

Mechanical Properties:

Density g/cc (#/in³): 3.89 (0.14)

Surface Finish - CLA:                                  Micrometers       Microinches 

              As-Fired:                                            0.9                       35

                Ground:                                            0.5                       20

              Polished:                                            0.1                       3.9

Crystal Size:

                 Range:                                            5-50                  197-1970

              Average:                                             17                        670

Water Absorption Percent: 0

Gas Permeability: 0

Color: Ivory

                                                                         MPa                    psi × 10³

Flexural Strength (Mor) at 20 ^oC:                      379                      55

                                                                         GPa                     psi × 10⁶

Elastic Modules at 20 ^oC:                                    372                      54

Shear Modules at 20 ^oC:                                      152                      22

Bulk Modules at 20 ^oC:                                        228                      33

                                                                          m/sec.                  ft/sec.

Trans. Sonic Vel. at 20 ^oC:                                 9.8 × 10³              32 × 10³

Poisson's Ratio at 20 ^oC: 0.22

Stiffness/Weight at 20 ^oC (GPa/g/cc): 96

Fracture Toughness at K_IC (MPA ⋅ m 1/2): 4-5 

                                                                              MPa                    kpsi

Compressive Strength at 20 ^oC:                            2620                  380

Tensile Strength: at 25 ^oC:                                     262                    38

                      at 1000 ^oC:                                         --                     --

                                                                             GPa                     kg/mm²

Hardness:           Knoop 1000 g:                            14.1                     1440

                           Rockwell 45N:                              83

 Thermal Properties: 

                                                                           W/m ^oK              Btu⋅in/ft²⋅h⋅ ^oF

Thermal Conductivity at 20 ^oC:                              35.6                     247

                                                                               10^-6/ ^oC               10^-6/ ^oF

Coefficient of Thermal Expansion at 25-1000 ^oC:   8.2                       4.6

                                                                                J/kg⋅ ^oK              cal/g⋅ ^oC

Specific Heat at 100 ^oC:                                            880                      0.21

                                                                                   ^oC                        ^oF

Thermal Shock Resistance, ΔTc:                                  200               392

Maximum use temperature:                                        1750              3182

Electrical Properties: 

Dielectric Strength:                                                ac-kv/mm           ac-volts/mil

              at 6.35 mm:                                                    8.7                       220

              at 3.18 mm:                                                    11.4                     290

              at 1.27 mm SPEC:                                          16.9                     430

              at 0.64 mm Thick:                                         22.8                     580

              at 0.25 mm:                                                    33.1                     840

                                                                      1 kHz                  1 MHz                 1 GHz

Dielectric Constant at 25 ^oC:                               9.8                  9.7                  9.7

Dissipation Factor at 25 ^oC:                             0.0002             0.0003             0.0002

Loss Index at 25 ^oC:                                         0.002               0.003               0.002

Volume Resistivity:                                                           ohm-cm²/cm 

              at 25 ^oC:                                                                   >10¹⁴

              at 300 ^oC:                                                               1.6 ×10¹³

              at 500 ^oC:                                                               2.1 × 10¹⁰

              at 700 ^oC:                                                               4.4 × 10⁸

              at 1000 ^oC:                                                                   --

Wear Chemical Properties: 

Corrosion Resistance - Weight Loss:                                 mg/cm²/day

              95% H₂SO₄ at 20 ^oC:                                                  0.01

              95% H₂SO₄ at 100 ^oC:                                                 0.1

Impingement: 0.47

Rubbing: --